How to Pressure Wash Car Engine Bay: Power Wash Car Engine Without Screwing It Up in 5 Easy Steps

By Miguel Hernandez

January 2, 2023

I know, we all know, everyone washes their cars. Someone must be out of their mind not to do so.pressure wash car engine

But, did you ever think of engine cleaning in the first place? This is like taking a bath without brushing your teeth!

Grease, dirt and oily build-up leave black coated filth on the engine. I suggest deep cleaning your car engine bay, which is an effective way of cleaning all the grime and grease.

Taking care of just the outside leaves the auto pretty and shiny for others but under the hood, the engine can be in a terrible situation. Using a pressure washer to wash your car engine might be the step for keeping the engine in good operating condition.

But, make sure you do the right way. Let’s see how it’s done the right way.

Is Power Washing Bad for My Car? (What the Manuals Say)

When my neighbors first saw me washing my car engine, they were like, OMG!

Never thought (they) that was a good idea. And kept asking me is it good or bad?

I don’t blame them that they do not know the right way of cleaning. Most of the car manuals do not cover this topic. But some says it can be washed after heavy slug with care.

Even shaving your beard has a right and wrong  way. The wrong way of shaving is going to cost you pain. Problems after power washing wont happen if you do it the right way. With care and preparation pressure washing car engine is safe and sound.

The Wrong and Right Way of Pressure Washing Engine

Why  should even bother for this? Isn’t pressure washing is super easy?

Yes. But every process has the right and wrong way to perform. Pressure washing is a safe process until you choose the wrong way.

So, what are the ways all about?

  • The wrong way includes a heavy-duty 3000 psi pressure washer, 0° blast nozzle tip. This combination is going to wreck the hell out of your car engine.
  • The right way of cleaning is using a 40° nozzle tip combining with a moderate psi electric or gas pressure washer, gently spraying water keeping the lance distance of at least 3 feet.

The right way ensures a properly cleaned car engine that looks stunning.

Engine Components to be Protected

The right way is the safe way. This way your engine components can be safe.

But, in this process, there is a key player-Water. Water jets are vulnerable to electrical components. Even worn bolts can be washed away by the force.IP rating for pressure washer

To better protect your electrical parts you have to understand exactly which components you need to get covered with a plastic bag.

For this first, you need to understand the IP rating. Then check the IP rating of your car’s electrical components and enclosures at the engine area. If there is not mentioned, assume it as less than IP5.

Any rating that is below IP 5, must be covered up with poly bags.

Refer to the image to understand the IP rating in detail.


Let me make it easier for you if you are still confused which parts to cover with wrapping polybag. In most of the cases, these components need to be wrapped for protection.

  • Alarm system
  • Loose electrical connection
  • Battery wiring
  • Distributor
  • Alternator

You also want to cover up the engine air filter in order to keep any water from going in there and sucking it up into the engine. Depending on how your air filter is shaped or where it’s located you might have to cover it in different ways but just make sure to cover up the entry into the air filter with a plastic bag.

Engine Cleaning With Engine Degreaser: Speed Up the Process

In order to deep clean an engine bay it is necessary  to use a degreaser in order to get the best results. Although not all the build up on the engine block may be grease, the degreaser does a great job at removing and cleaning any dirt and grime in the engine bay.

If you don’t use a degreaser then it will be also impossible to clean the engine bay because no matter how much pressure you use you the grease won’t go away unless its broken down with a degreaser first

Although the buildup on the engine block is not grease, unless you actually put it there, but the sludge appears as sticky as grease. And dust mixed up with the sludge makes it way too difficult to wash with only water. No matter how much pressure you put.

To make the job easier and effective using a chemical to wash loosen or remove the greasy build up is a wise move.

By using the term chemical I mean detergent or ready to use degreaser spray.

First, you need to identify the exact condition of your engine bay.

Is it Too Greasy and Oily Stained Engine?

For this situation, a normal/soft degreaser is not going to work effectively. You need a degreaser that is heavy duty.

Simple Green manufactures a degreaser for this purpose. This one is extremely effective with grease build up.


As it comes in concentrated form, you can easily dilute it to the desired level for proper degreasing. Also, this is not harmful to plants or landscape. Putting in some extra effort for this kind of heavy grime is worth it.

Use it in the pressure washer detergent tank with proper dilution ratio and use a scrubber to help the degreaser penetrate.

Is it Dusty but Not That Oily?

So, this might be when you washed your car engine not long before. Only dust build-up is not much of a mess.

For this condition, you can directly spray (spray bottle) degreaser in proper dilution. Scrub the engine for dust free look.

Super Clean Makes great products for this purpose.

This is super easy to spray directly. This degreaser is ready to use for engine bays and there is no need to dilute it. It’s a powerful cleaner that will get the job done and I have used it before in my own auto detailing business.



After spraying it on you can leave it for pressure washing or wipe it with a towel (though never reuse a degreasing towel on paint).

This Super Clean is a signature series degreaser is awesome in its purpose. This is also great for tires and rims.

Choose the Right Pressure Washer

Here’s the most important part. Choosing the right water source.


You do not need an industrial grade pressure washer, you don’t even need a pressure washer at all.  If you have a pressure washer with which you wash your car, just great. If you don’t, you might read our recommendation of the best pressure washer for a car.

Using a low PSI pressure washer is going to be the best for washing your engine bay but you can also just use a standard garden hose.

I recommend, having a pressure washer within the range of 2000 psi to 2200 psi. This range is safe. If you plan to buy a 3000 psi washer, then go for a pressure washer with easy control of psi.

Furthermore, use a 25° nozzle to start with.

That nozzle is going to fit with your spray gun or trigger gun whichever you use.

A Video Of Car Engine Bay Cleaning

Steps for Cleaning Car Engine Bay with Pressure Washer without Damage

1. Manage Everything You Need Before Starting

Gather everything that will be needed while pressure washing. You do not want to run and pick each thing while pressure washing.

2. Focus on Precautions

  1. Make sure to use a chemical which is non-corrosive
  2. The engine must be cooled down before spraying chemical or water
  3. Cover necessary electrical components with wrapping polybag and tape them

3. Agitate and Clean Engine Bay

Before pressure washing, spray the degreaser on the engine block. This will help loosen the grime for pressure washing.

Use a detail brush like an Ez detail brush or a work stuff detail brush you can find on amazon to agitate the dirt, grime or grease.

You want to make sure to get into all the cracks and crevices using those brushes to ensure the best results on your engine bay.

Also apply the degreaser especially to those places where it’s hard to reach

4. Rinse the Engine

Now, this is the time for pressure washing. Start with a 25° nozzle and if required, switch to a 40° nozzle. Always stand back from the engine keeping a distance of three feet.

Be sure to rinse away any of the degreaser, dirt and grime on the engine.

Making sure to not  pressure wash from a close range as that can damage engine parts.

5. Dry and Shine the Engine

You can use a leaf blower to dry the engine faster. You can also use a microfiber towel to dry the plastic parts.

Next step is to remove the plastic bags that were wrapped to protect electrical equipment and your air filter.

The last and final step after you have dried the engine bay is to get yourself a plastic dressing like Meguiars Hyper Dressing and apply this to all the plastic parts in the engine bay to give the engine that extra shine to finish the look.

Cleaning a car engine with a pressure washer can be pretty easy and isn’t that hard. It can be intimidating but always remember to keep a safe distance and cover the electrical equipment and air filter to make the job safer.


About the Author

Miguel Hernandez (Owner of A1 Auto Detailing)

I am the owner of an Auto Detailing company based in Everett, Washington, I have been detailing for many years now and have expertise in many aspects of auto detailing. I have seen and come across many types of situations in auto detailing and know pretty much how to deal with any type of car detailing